ML030860602
| ML030860602 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/04/2003 |
| From: | Cullen W Westinghouse |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| SG-SGDA-03-03-NP | |
| Download: ML030860602 (58) | |
Text
I to TXX-03064 SG-SGDA-03-03-NP Comanche Peak Steam Electric Station Unit 1 Cycle 10 Operational Assessment
eWestinghouse Westinghouse Non Proprietary Class 3 SG-SGDA-03-03-NP Comanche Peak Steam Electric Station Unit 1 Cycle 10 Operational Assessment January 2003 Prepared by: 1it
(/3 Ic 3 4t, W,
., Cullen Approned by:
111_
H, 0. L.agally TXU Approval:
.Z4-43' i2/I/3 S. M. SwIlley Westinghouse Electric Company LLC
SG-SGDA-03-03-NP Comanche Peak Unit I Cycle 10 Operational Assessment
1.0 INTRODUCTION
Per NEI 97-06, a condition monitoring assessment which evaluates structural and leakage integrity characteristics of SG eddy current indications is to be performed following each inspection. SG SGDA-02-43 provides an assessment of the Comanche Peak Unit 1 steam generator tube structural and leakage integrity based on the October 2002, EOC-9 eddy current inspection results. Condition monitoring is "backward looking" and compares the observed EOC-9 steam generator tube eddy current indication parameters against structural and leakage integrity commensurate with the NEI 97 06 performance criteria. Additionally, an operational assessment, or "forward looking" evaluation is used to project the inspection results and trends to the next inspection to determine primarily if tube structural or leakage integrity will be challenged at EOC-10. This report documents the operational assessment of SG tube integrity at EOC-10 that supports full cycle operation with the next SG inspection at Spring 2004.
The Comanche Peak Unit 1 SGs are Westinghouse Model D4 SGs with mill annealed Alloy 600 tubing, full depth mechanical (hardroll) expanded tube to tubesheet joints, and carbon steel tube support plates with drilled tube holes and drilled flow holes. A small number of tubes in each SG are expanded in the tubesheet using the WEXTEX explosive expansion process.
2.0
SUMMARY
OF 1RF09 CONDITION MONITORING EVALUATION Approximately 1 week prior to the planned shutdown for the 1RF09 outage, primary to secondary leakage was reported from SG 2. Over an approximate 2 day period, the leakage trending showed 6 spikes, with decaying leak rate following the spike. For the first 3 spikes of 5, 12, and 15 gpd, the leak rate decayed following the spike to less than 5 gpd. For the next 3 spikes of 25, 42, and 52 gpd, the leak rate began to decay but the duration between the spikes was reduced and the decay was not complete. The unit was taken off-line on September 28, 2002, prior to the primary to secondary leak rate reaching the EPRI Primary to Secondary Leakage Guideline limit of 75 gpd. The leak rate trending curve is provided in Figure 1.
Upon shutdown, once the SG manways were removed, water was observed to be dripping from tube R41 C71, SG2, cold leg side, at 2 to 3 drops per minute with the SG water level approximately 5 feet above the top of the tube bundle. The 2001 bobbin data was reviewed for this tube. A 1.13 volt, 1330 phase angle signal in channel 1 (550 kHz differential), 0.68 volt, 940 phase angle signal in channel 5 (130 kHz differential) was observed in the bobbin data. This signal was judged to be associated with the leakage source.
1RF09 bobbin data shows a 6.15 volt, 480 phase angle signal in channel 1, 3.27 volt, 450 phase angle signal in channel 5. The 1RF09 +Pt data showed a 6.5 volt, 92%TW, 0.91" long signal at the same elevation. At these signal amplitudes, it was concluded that this was the leakage source. Close scrutiny of the +Pt data suggests a possible ding presence at one tail of the indication. These flaw amplitudes will overpower any ding signal at the deeper portions of the flaw. In situ leak and proof testing of this tube was performed. At a pressure differential of 1439 psi, the maximum measured in situ leak rate was 0.03 gpm. The leak rate decayed to approximately 0.011 gpm at the end of the 5 minute hold period. As pressure differential was increased, the leakrate steadily increased, there were no discernable spikes observed during the pressure escalation. At a pressure differential of 2150 psi I of 46
SG-SGDA-03-03-NIP the measured leak rate was approximately 2.6 gpm. At this point, the high range flow meter operating range was exceeded and the test halted. During the pressure descent cycle, the pressure differential was held at 1200 psi for 2 minutes. During this period the leak rate was constant at 1.2 gpm. In short, the burst capability at 3 times normal operating pressure differential (3AP) could not be verified based on the tooling capacity, and the leakrate exceeded the performance criterion of 1 gpm at <simulated steam line break (SLB) conditions, based on in situ testing results. Thus the NEI 97-06 leakage performance criterion was not met and the NEI 97-06 burst performance criterion could not be verified. Following in situ pressure testing, a cable stabilizer was installed and the tube was plugged.
An extensive review of the 2001 bobbin reporting criteria was performed. The ding ODSCC inspection logic required that a ding signal be present in channel 1 for the signal to be evaluated as a potential ding flaw in channel 5. The bobbin reporting criterion for potential ding flaws is <1550 phase in the 130 kHz differential process channel. Due to probe wobble, a ding signal was not reported at this location in 2001. As a ding signal was not identified, the signal was evaluated as a freespan differential signal. In order for the freespan differential signal to be considered as a reportable indication, a depth of>0%TW must be observed in either channel 5 or channel 3 (300 kHz). The channel 5 phase angle was within 1' of reporting. Since a >0% depth report was not present in either channel 3 or 5, this signal was not reported as a possible indication. The Comanche Peak 1RF08 eddy current analysis guidelines allowed the analyst to flag any complex signal that did not meet the reporting requirements but may be flawed, based on the analyst's judgment. Review of the 1999 bobbin data for R41 C71 indicates a distorted signal in channel 5, suggesting that corrosion initiated prior to the 1RF07 (1999) inspection.
The 2002 bobbin reporting criteria were revised to include signals like those observed in 1999 and 2001 for R41 C71. The 2002 bobbin reporting criteria was based on phase response of channel 5 between 200 and 1600. This change resulted in a large number of freespan differential signal (FSD) reports. This change identified at least one other ding flaw (as confirmed by +Pt) in SG 2. Several other ding flaws were reported and confirmed in the U-bend region of large radius tubes, however, the probe wobble conditions were more conducive to identification of a ding signal and evaluation as a potential ding flaw. These signals were reported as DNI by bobbin. In 2001, a DNI was reported in R49 C44, SGl, and subsequently confirmed as axial ODSCC by +Pt. The probe wobble conditions in this tube are such that the ding signal was readily discernable, and thus evaluated as a DNI. In the 2001 inspection, 20 DNI signals were reported by bobbin and +Pt tested, but only R49 C44 was confirmed. These signals existed in both the straight leg section and U-bend regions. In all cases, the bobbin coil could identify a ding signal, thus the 2001 inspection data did not suggest an issue with probe wobble and ding obscurity.
The initial 2002 FSD reporting criteria also resulted in the identification and confirmation of 2 tubes with freespan axial ODSCC in the straight leg section of tube without the presence of a ding. One tube (Ri1 C42 SG2) had axial ODSCC in the span between H3 and H5 (2nd and 3rd hot leg TSPs) and between H5 and H7. The second tube (R7 C17 SG3) had axial ODSCC on both the hot and cold leg sections, at about the same elevation as R 1I C42. The indications appear to be axially aligned. R7 C17 was in situ pressure tested with no leakage or burst; R1 1 C42 was in situ leak tested (full tube mode) and was removed from the SG for destructive examination. Laboratory burst pressure was 8177 psi. Subsequent reanalysis of the 2002 bobbin data identified 4 additional tubes with freespan axial ODSCC. The most significant of these, R7 C1 12, was in situ leak and proof tested in a full tube mode with no leakage or burst. R7 C 112 also represented the limiting freespan axial ODSCC 2 of 46
SG-SGDA-03-03-NP indication. The changes made to the bobbin reporting criteria will identify these types of indications much sooner in their growth evolution. Review of bobbin data for R7 C1 12 indicated that precursor bobbin signals were present in the 1999 inspection.
The 1RF09 change to the bobbin reporting criteria will identify indications similar to the 1999 and 2001 signals for R41 C71, and thus help to ensure satisfaction of tube leakage and structural integrity requirements of these types of indications. The 1RF09 change to the bobbin reporting criteria will identify indications similar to the 2 initially reported freespan indications without the presence of a ding. Based on in situ test results and calculated burst capabilities of these flaws, continued satisfaction of SG leakage and burst capability requirements is expected.
A large increase in the number of reportable circumferential ODSCC indications was noted at the hot leg top of tubesheet locations. All indications were judged to meet the structural and leakage performance criteria based on calculated percent degraded area of each indication from reported eddy current parameters and reported flaw amplitudes. None were required to be in situ pressure tested, however, 8 conservative in situ tests for this mechanism were performed. No leakage or burst occurred. An additional circumferential indication was in situ leak tested only. This indication was located in tube R1 1 C42, SG2. This tube was pulled for destructive examination of freespan axial ODSCC indications.
Freespan axial ODSCC indications were reported on a total of 6 tubes in 2 different SGs. Five of these were in situ leak tested with no leakage reported. Four were in situ proof tested with no burst reported. As stated above, one tube was in situ leak tested only since the tube was removed for destructive examination. The remaining indication not in situ pressure tested was not required to be tested based on the reported flaw parameters and was judged to be bounded by all other freespan axial ODSCC indications.
A total of 2 axial PWSCC indications were reported at the hot leg top of tubesheet expansion transition. Neither was required to be in situ pressure tested.
The AVB and baffle plate wear mechanisms did not show excessive growth, and growth trends were consistent with Cycle 8. Two baffle plate wear indications required plugging due to measured wear scar depth of41%TW (SG4), and 40%TW (SG2). No AVB wear signals exceeded 40%TW.
During the CPSES IRF09 steam generator tube inspection, with the exception of R41 C71 SG2, no indications exceeding the structural integrity limits for either axial or circumferential degradation (i.e., burst integrity > 3 times normal operating primary to secondary pressure differential across SG tubes) were detected. Based on the changes made to the bobbin reporting criteria and the observed signal characteristics for the top of tubesheet ODSCC mechanisms, which will be discussed in detail later, it is expected that all operational assessment structural and leakage integrity requirements will be satisfied at EOC-10 for the degradation mechanisms observed at EOC-9.
Based on the observed flaw parameters reported at 1RF09 and operational assessment provided herein, it is concluded that all 1RF09 observed degradation mechanisms will provide structural and leakage integrity at EOC-10.
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SG-SGDA-03-03-NP 3.0 1RF09 SG INSPECTION PROGRAM and 1RF09 OBSERVED DEGRADATION MECHANISMS The following summarizes the initial planned inspection scope and expanded inspection scope for the IRF09 outage.
CPSES 1RF09 Initial Inspection Plan The CPSES IRF09 inspection plan exceeded both the Technical Specification minimum requirements as well as the recommendations of EPRI TR-107569-V1R5, PWR Steam Generator Examination Guidelines: Revision 5, Volume 1: Requirements. The IRF09 initial inspection plan included;
- 1) 100% full length bobbin examination in Rows 3 and greater in all 4 SGs, 100% bobbin inspection in the hot and cold leg straight sections of Rows 1 and 2
- 2) 100% hot leg top of tubesheet (TTS) RPC examination in all 4 SGs from +3 to -3" for hardroll expanded tubes from +3 to hot leg tube end for WEXTEX expanded tubes
- 3) 100% Row 1 and 2 U-bend mid-range +Pt examination in all 4 SGs
- 4)
Rotating probe examination of mixed residuals (> 1.5 volts as measured by bobbin) and hot leg dented intersections > 5 volts (as measured by bobbin) according to the requirements of GL 95-05.
- 5)
Rotating probe examination of freespan bobbin coil indications for flaw confirmation and characterization.
- 7) 100% +Pt inspection of>5V hot leg dings from HTS to AV2 and >5V cold leg dings from CTS to C8, plus 20% +Pt inspection of freespan dings > 5 volts between AV2 and AV3 and C8 and C9
- 8) 20% +Pt freespan paired ding inspection between the top 2 TSPs
- 9) 25% +Pt inspection of expanded cold leg baffle intersections
- 10)
Tube plug visual inspection The inspection plan was developed to specifically address the areas of active degradation as well as areas expected to be affected based on recent industry experience as well as experience from the CPSES 1RF08 outage in April 2001.
A C-3 condition was reported in SGs 2, 3, and 4 due to the detection of>45 circumferentially oriented ODSCC indications. The 1RF10 top of tubesheet +Pt inspection program will include 20%
of the cold leg TTS expansion transitions in these SGs.
Based on the observed 1RF08 eddy current signals from the leaking tube, observation of axial ODSCC in a 6.2 volt ding within the critical area, and observation of axial ODSCC in small dings adjacent to >5V dings, the >5V ding +Pt program was expanded to include all >5V dings, at all locations. Additionally, 100% of the U-bend FSD signals and 20% of the >2 volt dents/dings between C11 and AV2 were inspected with +Pt. Another 20% sample of the dents/dings >0.75 volt and <5 volt within 0.75" of structures were also examined with +Pt.
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SG-SGDA-03-03-NP Indications suggestive of the following degradation mechanisms were detected in the CPSES IRF09 inspection:
"* Axial ODSCC at TSP intersections
"* Axial ODSCC at the Hot Leg TTS expansion transition
"* Circumferential ODSCC at the Hot Leg TTS expansion transition
"* Axial PWSCC at the Hot Leg TTS expansion transition
"* Axial ODSCC in the freespan not associated with dings
"* Axial ODSCC at freespan dings
"* Freespan Volumetric indications (not associated with operational degradation)
"* AVB wear
"* Wear at non-expanded preheater baffle intersections
"* Wear due to loose parts or foreign objects The 90-day report for axial ODSCC at TSP intersections will be documented in a separate ARC report, as part of analyses required per NRC Generic Letter 95-05. Tube support plate ODSCC indications for 1RF09 were nearly identical to 1RF08, both in total number of indications and observed bobbin amplitude. Only 1 indication had bobbin amplitude greater than 1 volt. This indication, in SG 4, was confirmed by +Pt and plugged.
Table 1 presents a summary of the number of repaired tubes in each SG and identifies the mechanism that necessitated the repair. A summary of all repaired tubes, including tubes plugged for degradation, tubes preventively plugged, and tubes permitted to remain in service by application of the voltage based alternate repair criteria per GL 95-05, and F*, is provided in Table 2.
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SG-SGDA-03-03-NP Table 1 Summary of 1RF09 Tube Repair Statistics Based on Observed Degradation (Values do not reflect sleeve installation in SGs 2, 3, and 4)
SG 1 Degradation HL sludge pile HL TTS Exp.
Small Radius Hot Leg Freespan Straight Leg U-bend Baffle Total Mode
(>1" above TTS)
Transition U-bend TSP (no ding)
(ding)
(ding)
Plate Axial ODSCC 0
0 0
0 0
6 4
0 10 Axial PWSCC 0
0 0
0 0
0 0
0 0
Circ. ODSCC 0
31 0
0 0
0 0
0 31 Wear 0
0 0
0 1 (1) 0 0
0 1
Volumetric 0
0 0
0 2(2) 0 0
0-2 Sub Total 0
31 0
0 3
6 4
0 44 SG2 Axial ODSCC 0
2 0
0 2(3) 2 2
0 8
Axial PWSCC 0
1 0
0 0
0 0
0 1
Circ. ODSCC 0
187 0
0 0
0 0
0 187 Wear 0
0 0
0 0
0 0
1 1
Volumetric 0
0 0
0 2(2) 0 0
0 2
Sub Total 0
190(3) 0 0
4 2
2 1
199(4)
SG3 Axial ODSCC 0
2 0
0 4
0 0
0 6
Axial PWSCC 0
1 0
0 0
0 0
0 1
Circ. ODSCC 0
216 0
0 0
0 0
0 216 Wear 0
0 0
0 1 (1) 0 0
0 1
Volumetric 0
1 (1) 0 0
4 0
0 0
5 Sub Total 0
220 0
0 9
0 0
0 T 229 (5)
SG4 Axial ODSCC 0
3 0
1 0
0 1
0 5
Axial PWSCC 0
0 0
0 0
0 0
0 0
Circ. ODSCC 0
234 0
0 0
0 0
0 234 Wear 0
0 0
0 1 (1) 0 0
1 2
Volumetric 0
0 0
0 4(2) 0 0
0 4
Sub Total 0
237 0
1 5
0 1
1 245 Overall Total 0
678 0
1 21 8
7 2
717(4,5) 6 of 46
SG-SGDA-03-03-NP Notes for Table 1:
(1): Foreign object/loose part wear above a structure (2): Baseline reviewed for these signals, indication existed in baseline data, therefore, not corrosion related.
(3): One tube with freespan ODSCC also had a circumferential ODSCC indication at the top of tubesheet (4): One tube in SG 2 had a freespan axial ODSCC flaw and a circumferential ODSCC flaw at the top of tubesheet (5): One tube in SG 3 had a freespan axial ODSCC flaw and a circumferential ODSCC flaw at the top of tubesheet 7 of 46 Table 2 Summary of Repaired Indications and Indications Justified for Continued Operation by Application of ARCs:
CPSES 1RF09, October 2002 Values Apply to 1RF09 Ins ection Only SG Tubes Tubes Repaired Tubes Repaired Tubes Tubes Permitted to Tubes Total Tubes Repaired by for Crack-like for Volumetric Preventively Remain in Service by Permitted to Permitted to Plugging Defects Signals Including Plugged TSP ARC Remain in Remain in Service Wear Service by F*
by ARCs (4) 1 48 41 3
4 (1) 28 (28 indications) 0 28 2
18 15 3
0 25 (25 indications) 0 25 3
22 15 5
2 (2) 21 (21 indications) 0 21 4
12 (3) 5 6
0 144 (159 indications) 0 144 Total 100 77 17 5
218 (233 indications) 0 218 (1) Includes one tube preventively repaired due to possible ding ODSCC (2) Includes 2 tubes repaired due to PVN (3) Includes 1 tube plugged by mistake.
(4) Final tube count may be influenced by plugging for other reasons.
SG-SGDA-03-03-NP 4.0 OPERATIONAL ASSESSMENT EVALUATION 4.1 Operational Assessment of Observed Stress Corrosion Cracking Mechanisms 4.1.1 TTS Circumferential Flaw ODSCC Operational Assessment Evaluation Structural integrity of circumferential indications at the TTS is defined by EPRI TR-107197,"Depth Based Structural Integrity of Circumferential Indications". The controlling parameter with regard to structural integrity of circumferential indications is the percent degraded area, or PDA. The PDA represents the percentage of degraded cross sectional area of the tube.
The burst correlation for circumferential indications is documented in EPRI TR-107197, "Depth Based Structural Analysis Methods for SG Circumferential Indications". The burst curve was used to develop the 100%TW critical crack angle value of 2940 (82% PDA) for CPSES Unit 1 at 3AP conditions using mean material property values.
Screening of indications for selection as in situ test candidates is performed at CPSES Unit 1 using a methodology which is consistent with EPRI Report TR-107620-R1, "Steam Generator In Situ Pressure Test Guidelines". The PDA screening limit is developed by reducing the 82% PDA for material properties at the lower tolerance limit (LTL) values and NDE uncertainty at the 95%
probability level. The resultant PDA used for in situ screening purposes is 56%.
No circumferential indications were required to be in situ pressure tested at 1RF09. It was concluded that in situ testing would conservatively be performed at 1RF09 to validate the conservatism in the sizing methodology. A total of 8 tubes with circumferential ODSCC at the top of tubesheet were in situ pressure tested with no leakage at 2970 psi and no burst at 4375 psi. The tubes were selected using the following criteria:
- 1. The three largest PDA values
- 2. The three largest flaw amplitudes
- 3. Additional tubes with large flawed arc extents that were judged to have less segmentation than others. A total of 2 tubes were selected in this category.
Table 7 presents a summary of the in situ testing performed at 1RF09 and past outages, and this table includes the pertinent flaw data.
The sizing performance evaluation for circumferential ODSCC at the top of tubesheet expansion transition is dominated by pulled tubes from plants with significant OD deposits. Two pulled tubes from Comanche Peak 1 are also included in this dataset. The sizing performance of these 2 tubes show very small errors comparing truth to NDE developed values. The minimal OD deposit condition at Comanche Peak 1 also influences the probability of detection, suggesting that the probability of detection at Comanche Peak 1 is likely improved compared to other plants with Alloy 600 mill annealed tubing.
Assumed Beginning of Cycle Indication Distribution Figure 2 presents a comparison of the 1RF08 and 1RF09 circumferential ODSCC flaw +Pt amplitude 8 of 46
SG-SGDA-03-03-NP distributions. At 95% cumulative probability the 1RF09 amplitude distribution is bounded by the 1RF08 distribution. The cumulative probability distribution functions for +Pt amplitude for each of the last 3 Comanche Peak 1 inspections are essentially equal suggesting that the distributions of observed flaws has not changed over the last 3 inspections, and thus, the growth function has remained essentially constant over this period. Above 95% cumulative probability, the IRF09 distribution is limiting based on the observation of 3 indications at 1RF09 with +Pt amplitudes that exceeded the largest 1RF08 +Pt amplitude. Figure 3 presents the 1RF09 circumferential ODSCC PDA distribution. Since the detection capability of the +Pt coil for indications <40%TW is limited, the PDA distribution of Figure 3 is developed by assigning a depth of 40%TW for indications with reported depth <40%TW in the calculation of PDA. This adjustment will produce a more realistic representation of the true PDA distribution but will not influence the PDA distribution at cumulative probability levels above about 50%. At 95% cumulative probability, the corresponding PDA value is 26%. The NDE adjusted PDA value at the upper 90% probability, 50% confidence level is 51.9%.
Figure 4 presents a plot of the +Pt amplitude versus PDA for the Comanche Peak IRF09 PDA values at the upper 90% probability, 50% confidence and the pulled tube database. This plot shows that the upper Comanche Peak 1RF09 population of NDE adjusted PDA values lies within the bounds of the pulled tube PDA values from destructive examination. The only indication that lies outside of the pulled tube bound was reviewed and it has been concluded that the maximum depth estimate for this tube (R24 C82 SG2) of 86% is unreliable for the indicated maximum voltage of 0.12 volts (i.e., the large indicated depth should have produced a larger amplitude). Additionally, the profile shows multiple initiation sites that result in a likely overestimate of the true PDA.
Growth Evaluation Of the 668 reported circumferential ODSCC indications, a total of 260 indications were included in a growth evaluation. The selection criteria for the growth evaluation was all indications with a +Pt flaw amplitude of> 0.20 volts and all indications with a reported flaw involvement angle of> 1800.
Figure 5 presents the +Pt amplitude growth for Cycle 9, and Figure 6 presents the PDA growth for Cycle 9.
Operational Assessment The operational assessment for circumferential ODSCC indications at the top of tubesheet expansion transition was performed using 2 independent paths that follow a methodology consistent with the EPRI Tube Integrity Assessment Guideline. A deterministic methodology is applied.
PDA Path:
The 95% cumulative probability distribution function based on NDE adjusted PDA is 51.9%. The PDA growth at the 95% cumulative probability value is 14%. Therefore, the projected PDA value at EOC-10 is 65.9%, which is less than the structural limit PDA reduced for material properties at the lower tolerance limit of 78%, and structural integrity at EOC-10 is confirmed.
+Pt Amplitude Path:
Figure 7 provides a correlation of +Pt amplitude versus burst pressure for the pulled tube database.
The correlation coefficient (R = 0.90 with 18 data points; minimum acceptable value is 0.47) 9 of 46
SG-SGDA-03-03-NP indicates that the correlation is valid. The 95% cumulative +Pt amplitude based on the 1RF09 amplitude distribution is 0.25 volts. The 95% cumulative amplitude growth is 0.13 volts, therefore, the EOC-10 projected maximum flaw amplitude is 0.38 volts. The burst capability at the lower 90%
probability, 50% confidence level corresponding to a +Pt flaw amplitude of 0.38 volts is approximately I
]a,c,e Therefore, structural integrity at EOC-10 is confirmed. Figure 7 also includes a correlation of +Pt amplitude versus PDA from destructive examination. At 0.38 volts, the predicted PDA at the upper 90% probability, 50% confidence level is approximately [
ae which is less than the structural limit of 78%, and structural integrity at EOC-10 is confirmed. It should be noted that the PDA values included in Figure 7 do not include non-degraded ligaments, and are conservative. If the maximum reported 1RF09 +Pt amplitude of 0.56 volts is combined with the largest growth value of 0.22 volts resulting in a maximum postulated EOC-10 amplitude of 0.78 volts, the maximum postulated EOC-10 burst capability is I Ia,c,e and the maximum postulated EOC-10 PDA is 74%. Therefore, structural integrity at EOC-10 is confirmed.
For circ ODSCC, maximum +Pt amplitude is likely a more representative tool for assessment of leakage potential than depth from phase due to the highly segmented nature of the circumferential ODSCC at Comanche Peak Unit 1. Available industry in situ test data indicates that maximum +Pt amplitudes of up to 1.38 volts had no leakage. Available pulled tube data indicates no leakage at SLB conditions for +Pt amplitudes up to 2.51 volts. A 1990 pulled tube from a plant with Model D2 SGs leaked at 0.126 gpm (181 gpd) at SLB conditions. As only pancake coil data is available for this tube due to the timeframe, the +Pt amplitude is estimated using a scaling procedure (Reference 10). The estimated +Pt amplitude for this indication is 1.99 volts. The maximum postulated circumferential ODSCC +Pt amplitude at EOC-10 has been determined to be 0.78 volts. Therefore, it is judged that there will be no primary to secondary leakage contribution from circumferential ODSCC indications at EOC-10. As a verification of this conclusion, the statistically developed POD curve for ODSCC at a POD of 0.95 provided by Reference 1 can be used to establish an upper bound maximum depth postulated to be left in service of 53%TW. The maximum depth growth for 1RF09 circumferential ODSCC flaws at 90% probability, 50% confidence has been determined to be 30.4%. Therefore, the maximum postulated maximum depth of circumferential ODSCC at EOC-10 is determined to be approximately 83%TW. Thus, it is concluded that circumferential ODSCC will not contribute to postulated primary to secondary leakage at EOC-10 conditions.
4.1.2 Expansion Transition Axial Flaw ODSCC Operational Assessment Evaluation At the CPSES 1RF09 inspection, 7 axial ODSCC indications at the expansion transition were reported. The largest +Pt amplitude was 0.42 volts. All indications were profiled. The longest reported axial ODSCC flaw length from profiling was 0.27", which is well less than the 1 00%TW critical flaw length, reduced for length measurement uncertainty of 0.43" (Reference 8). Therefore, structural integrity of these indications is provided. Maximum reported depth of these indications was well below the in situ screening limit, and therefore, leakage integrity is also established. The
+Pt depth profiles for these indications suggests very shallow depths.
History reviews were performed for each of the reported 1RF09 axial ODSCC indications. This review concluded that precursor signals were present for each of the reported 1RF09 indications. The history data was used to establish +Pt amplitude growth, length growth, and maximum depth growth.
The average depth in 1RF08 was determined by applying a maximum to average depth ratio of 1.2 to 10 of 46
SG-SGDA-03-03-NP the 1RF08 maximum depth report. The value of 1.2 is determined as the average of the maximum to average depth ratios for the 1RF09 indications using amplitude based sizing.
Growth In general, growth appears minimal for these indications. The largest singular amplitude growth was 0.07 volts, and the largest singular length growth was 0.09". Maximum depth growth based on phase angle analysis indicates only one growth >10%TW/cycle, with a value of 26%TW. The 1RF09 maximum depth report was 26%TW, while the IRF08 maximum depth report was 0%TW. Use of this growth value as reported is conservative since the progression of the lissajous shows a vertical response, which is not achieved unless some depth is coincident. This indication had no voltage change for Cycle 9. Maximum depth growth based on amplitude sizing shows no singular growths exceeding 10%/cycle, which is expected since the amplitude growths are so small. Average depth growth based on phase analysis indicates no singular growth exceeded 10%. Average depth growth based on amplitude sizing produced results similar to the maximum depth growths.
Operational Assessment The distribution of 1RF09 axial ODSCC flaw lengths ranged from 0.09" to 0.27", with an average length of 0.19". The 90% probability, 50% confidence length value for the 1RF09 flaws is 0.27",
which is equal to the longest reported 1RF09 flaw. A value of 0.25" will be used as a beginning of cycle flaw length since the upper 90% probability, 50% confidence flaw length is equal to the maximum reported length. At this probability and confidence level the flaw length should be well less than the maximum value. Using the uncertainties developed in the degradation assessment, the NDE adjusted length is 0.36". Applying the singular largest length growth of 0.09" results in an EOC flaw length of 0.45". As the operational assessment projects expected true flaw lengths, the EOC-10 projected flaw length is compared against the 100%TW critical flaw length without NDE uncertainty.
This value is determined to be 0.497" using lower 90% probability, 50% confidence adjustments to material properties and relational error. As the projected EOC-10 length is less than the 100%TW critical flaw length structural integrity is confirmed at EOC-10. For comparison purposes only, the EOC-10 projected flaw length of 0.45" will be modeled to include projected EOC-10 average depth for burst pressure evaluation. The amplitude based sizing results produced deeper flaw estimates than the phase based sizing, and will be used to estimate the BOC flaw maximum and average depths.
The largest reported max depth at 1RF09 was 62%TW, while the 90% probability, 50% confidence max depth is 60%. Using the assumed BOC depth of 60%, and applying the largest amplitude based growth of 3.3%, the EOC-10 maximum depth is estimated to be less than 64%TW. Thus, there is no leakage potential from axial ODSCC at the TTS at EOC-10. If the singular largest amplitude growth of 0.09 volts is combined with the maximum 1RF09 voltage of 0.42 volts, the resultant maximum voltage of 0.51 volts has an estimated maximum depth of 75%TW at the upper 90% probability, 50%
confidence level. Therefore, maximum postulated EOC-10 flaw amplitude can also be used to support the conclusion that operational leakage is not postulated for sludge pile and top of tubesheet axial ODSCC indications.
The largest reported average depth at 1RF09 was 48.72%, while the 90% probability, 50% confidence average depth is 47.44%. The singular largest average depth growth is 3.94%, thus the EOC-10 average depth is estimated to be less than 52%. Using the part throughwall burst model, a 0.45", 52%
average depth flaw has a burst capability of 5856 psi using lower 90% probability, 50% confidence adjustments to material properties and relational error.
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SG-SGDA-03-03-NP In summary, structural and leakage performance criteria are satisfied at EOC-10 conditions for axial ODSCC at the hot leg top of tubesheet expansion transition.
4.1.3 TSP ODSCC Operational Assessment Evaluation Only 1 indication exceeding 1.0 volt (1.06 volts) was reported by bobbin (R38 C41 at H3 in SG 4).
This indication was confirmed by +Pt (0.15 volts, 1230 phase angle) and repaired by plugging. The voltage based structural limit for TSP ODSCC indications is 4.57 volts for a SLB AP of 2560 psi (with safety factor applied). The largest bobbin DSI voltages and total DSI reports for each SG are provided below in Table 4.
This data shows that SG 4 appears to be the most susceptible SG with regard to ODSCC initiation.
For all SGs, the average absolute voltage growth is -0.02 volts.
Mixed residual indications with a bobbin voltage > 1.5 volts are RPC inspected. No mixed residuals
>1.5 volts were reported to contain axial ODSCC based on the RPC sampling.
A complete evaluation per the GL 95-05 requirements will be provided in the ARC 90-day report.
The 1RF09 TSP ODSCC bobbin amplitudes are essentially equal to the 1RF08 values. Past GL 95 05 analyses have indicated that the projected leak rate at end of next cycle conditions will be approximately 0.001 gpm, and conditional burst probability of several orders of magnitude less than the GL 95-05 burst limit. The 1RF09 DSI distribution shows little or no variance from the 1RF08 distribution, and Cycle 9 DSI voltage growth rates are very similar to the Cycle 8 growth rates.
Considering the trivial bobbin amplitudes reported for the 1RF09 DSIs, there is no basis to conclude that the final GL 95-05 90-day report will differ in its overall conclusion from past analyses.
Table 4 1RF09 TSP ODSCC Degradation Summary 4.1.4 Freespan Axial ODSCC Operational Assessment (without presence of dent or ding)
A total of 6 tubes were reported with freespan axial ODSCC indications at 1RF09. Table 9 presents a summary of the reported 1RF09 indications. With the exception of R4 C51 SG3 and R7 Cl 12 SG3, multiple indications were reported in each tube. A similar degradation mechanism was observed in 2 other plants with Model D SGs with an axial OD scratch or gouge identified as a possible 12 of 46 SG 1 SG2 SG 3 SG4 Number Ind.
28 25 21 160 Number> I volt 0
0 0
1 Max 1RF09 Voltage 0.45 0.74 0.84 1.06 Average Voltage Growth Cycle 9 (per
-0.01 volts
-0.06 volts 0.01 volts
-0.02 volts Cycle)
Average % Voltage Growth Cycle 9 1.7%
0.51%
11.3%
-1.95%
(per EFPY)
I I
I I
SG-SGDA-03-03-NP contributing mechansim. The source of the OD scratch or gouge is believed to be related to increased difficulty associated with tube insertion during manufacture from the increased number of tube to tube support/baffle intersections inherent to the preheater design.
All freespan axial ODSCC indications with the exception of R4 C51 were in situ pressure tested in a full tube mode. No leakage was reported at 2841 psi. All pressure tested tubes with the exception of Ri1 C42 were in situ proof tested with no burst reported. Ri1 C42 was removed from the SG for destructive examination. The laboratory burst pressure of the section containing the flaw at H5 +
10.63" was 8177 psi at room temperature conditions. The burst pressure at 650'F is expected to be no less than 7360 psi. The yield and ultimate strengths determined from the pulled tube were 54.2 and 100.8 ksi, respectively, for a flow stress of 77.5 ksi. The certified material test report values for the heat that this tube came from are yield strength of 53 ksi, ultimate strength of 98 ksi, and flow stress of 75.5 ksi.
A bobbin history review of each indication was performed to determine growth rates and initiation trends. Table 10 presents a summary of the bobbin history review for each freespan axial ODSCC indication.
As seen from this table, all 1RF09 freespan axial ODSCC indications with +Pt amplitude of >0.10 volts had corresponding bobbin signals. All 1RF09 freespan axial ODSCC indications with +Pt amplitudes >0.13 volts had corresponding bobbin signals in IRF08. The most significant freespan axial ODSCC indication reported at IRF09 (R7 C1 12 SG3) had a corresponding bobbin signal in 1RF07.
The operational assessment for freespan axial ODSCC will utilize a methodology based on bobbin coil amplitude for development of growth rate data since +Pt data does not exist in history for the 1RF09 reported freespan axial ODSCC indications. Two separate methods will be used. One uses expected freespan axial flaw average depth and length at EOC-10 to calculate an expected burst pressure. Maximum depths are estimated based on a correlation of bobbin amplitude and flaw depth based on the available pulled tube data. The other uses a relation between bobbin amplitude and burst capability based on destructive examination data from the McGuire 1992 pulled tubes and the Comanche Peak lRF09 pulled tube.
Figure 8 presents a plot of the 130 kHz bobbin amplitudes versus maximum depth from destructive examination for the McGuire 1992 pulled tube freespan axial ODSCC degradation. The R2 value of 0.931 indicates a valid correlation exists. A beginning of cycle 130 kHz bobbin amplitude of 0.2 volts will be assumed for the evaluation since this value represented the amplitude cutoff employed in the original bobbin analysis automatic data screening. From Figure 8, the depth associated with a 0.20 volt, 130 kHz indication is 62% at the upper 90% probability, 50% confidence level. The final bobbin reanalysis performed on the 1RF09 data used a history review from 1RF09 to the first in service inspection of that tube, therefore, any indication with any measure of phase or voltage change would have been identified in this review. The Cycle 9, 95% probability, 95% confidence 130 kHz amplitude growth for the 1RF09 freespan indications is 0.14 volts. Therefore, it is postulated that a 0.34 volt, 130 kHz amplitude bobbin signal could be postulated at EOC-10. Using the upper 90%
probability, 50% confidence trend line of Figure 8, the maximum depth corresponding to a 0.34 volt bobbin signal is 74%TW. For freespan indications, a maximum to average depth ratio of 1.4 is applied based on the amplitude based depth sizing of RI 1 C42, R7 CI 12, and the maximum to average depth ratio of the McGuire pulled tubes. The destructive exam depth profile over the length consistent with the NDE profile indicates a maximum to average depth ratio of 2.09. Therefore, use 13 of 46
SG-SGDA-03-03-NP of a maximum to average depth ratio of 1.4 is conservative, and an average depth of 53%TW could be postulated at EOC-10. Since burst capability of axial indications is a function of both length and depth, an assumed flaw length must be considered. At the 95% cumulative probability based on the reported 1RF09 flaw lengths, the flaw length assumed is 1.75 inch. Using the Westinghouse part throughwall burst equation, the predicted burst capability of a 1.75" long, 53% average depth flaw using the lower 90% probability, 50% confidence flow stress value is 5986 psi, which is greater than the 3AP performance criterion, thus structural integrity at EOC-10 is confirmed. This approach uses the entire reported flaw length from +Pt analysis and is therefore conservative since shallow flaw tails that do not influence burst capability are included in the assumed EOC-10 length. Flaw depths
<40%TW typically do not influence burst capability. Figure 13 indicates that the total flaw length exceeding 40%TW depth is approximately 0.31", thus the use of the total flaw length of 1.75" is extremely conservative. If the projected EOC-10 average depth of 53% is applied to a length of 1",
the predicted burst capability of using lower 90% probability, 50% confidence material property values is 6178 psi, and for a length of 0.75", the predicted burst capability is 6318 psi.
The 130 kHz McGuire data from the time of the tube pull (May 1992) was used for this evaluation since the January 1992 (time of plugging) eddy current data used 100 kHz, 300 kHz, and 400 kHz as the prime analysis channels and 130 kHz data is available for a direct comparison with Comanche Peak. Also, additional crack growth may have occurred from the time of plugging to the time of the tube pull. The prime analysis channels for detection of freespan ODSCC used at Comanche Peak Unit 1 are 130 and 300 kHz differential. The McGuire January 1992 300 kHz data can also conservatively be used for evaluation of maximum depths at Comanche Peak. The Comanche Peak data indicates that the average 300 kHz to 130 kHz bobbin amplitude ratio is 1.50. Figure 9 presents a plot of the McGuire pulled tube data plotting 300 kHz bobbin amplitude from January 1992 versus destructive examination max depth from May 1992. Note that if additional corrosion occurred between January and May 1992 that the Figure 9 relation is conservative. The 1RF09 Ri1 C42 pulled tube data and R7 C1 12 data using the maximum depth at the upper 90% probability, 50%
confidence based on the amplitude vs depth correlation are provided in Figure 9 for comparison. The Comanche Peak data is slightly below the McGuire data suggesting that additional corrosion may have occurred in the McGuire pulled tube. The Cycle 9, 95% probability, 95% confidence 300 kHz amplitude growth for the 1RF09 freespan indications is 0.20 volts. Therefore, it is postulated that a 0.50 volt, 300 kHz amplitude bobbin signal could be postulated at EOC-10. Using the upper 90%
probability, 50% confidence line of Figure 9, the maximum depth corresponding to a 0.50 volt 300 kHz bobbin signal is 77%TW (versus 74%TW based on 130 kHz). Using the above discussion, average depth is estimated to be 55%, and predicted burst capability for a 1.75" long flaw at the lower 90% probability, 50% confidence material properties is 5772 psi. Therefore, structural integrity at EOC-10 is confirmed. If the Comanche Peak pulled tube max depth data for 130 and 300 kHz is added to the depth versus bobbin amplitude relationships of Figures 8 and 9 the maximum depth estimates are reduced by about 1.5%TW at 0.30 volts and by about I%TW at 0.7 volts. Therefore combination of the Comanche Peak pulled tube data and McGuire pulled tube data will not influence the operational assessment, and use of the McGuire data only provides an additional conservatism.
A cumulative probability distribution plot of the reported flaw maximum depths developed from a correlation of +Pt amplitude to maximum depth for IRF09 indicates that at 95%, the maximum depth lies within the 60 to 65%TW bin. The depths estimated from bobbin at the upper 90% probability, 50% confidence level are 62% using 130 kHz, and 65% using 300 kHz. Therefore, the maximum depth estimates based on bobbin coil data are consistent with the maximum depths estimated from the
+Pt coil.
14 of 46
SG-SGDA-03-03-NP Figure 10 presents a plot of the McGuire pulled tube 130 kHz bobbin amplitudes versus calculated burst pressure divided by 3AP. This plot can be used to define the 130 kHz bobbin amplitude that defines a burst capability of 3AP based on the lower 90% probability, 50% confidence flow stress at EOC-10 conditions. The destructive examination depth profiles were used to estimate burst pressure.
The actual tube material property data was adjusted to a two times flow stress of 134 ksi, which is the lower 90% probability, 50% confidence flow stress value. From Figure 10, a 0.34 volt bobbin signal has a burst pressure ratio of 1.46, suggesting a burst pressure of approximately 5548 psi, which is in good agreement with the burst pressure at EOC-10 based on predicted average depth and flaw length of 5986 psi at EOC-10. Figure 10 also includes the laboratory burst pressure of Comanche Peak pulled tube Ri1 C42, adjusted to a flow stress of 134 ksi. As seen from Figure 10, the adjusted burst pressure of Ri1 C42 lies significantly above the lower 90% probability, 50% confidence burst pressure relation. It should be noted that the indication in R7 Cl 12 was the only 1RF09 indication with 130 kHz bobbin amplitude greater than 0.34 volts. Figure 11 is similar to Figure 10 in that the 300 kHz bobbin amplitude data is plotted against the ratio of predicted burst pressure to 3AP. At 0.50 volts, the ratio is 1.26, suggesting a burst capability of 4788 psi.
Review of the field analysis data indicates that each of the auto data screening 130 kHz FSD indications >0.20 volts were reported as DFI (causing +Pt inspection) in either the tertiary resolution or history report. Therefore, the 130 kHz, 0.20 volt cutoff represents a detection with confirmation threshold.
The Cycle 10 freespan axial ODSCC operational assessment has been performed in two separate methods, for both 130 kHz and 300 kHz bobbin data. In all cases, the predicted burst capability at EOC-10 is greater than the 3AP value, thus structural integrity is confirmed.
Statistically Based Operational Assessment Approach:
Two separate deterministic paths were followed to establish structural integrity of freespan axial ODSCC indications EOC-10. As a confirmation of the deterministic paths, a statistically based approach will be utilized based on bobbin coil probability of detection (PoD). In order to establish a basis for the assumed detectability conditions, a summary of the 1RF09 bobbin program must be provided. The original bobbin analysis program used auto data screening as the primary analysis and manual analysis as the secondary analysis. A 0.20 volt, 130 kHz cutoff was applied to signals in the 130 kHz differential channel for the auto data screening. The +Pt evaluation of Ri1 C42 showed that there were +Pt SAI calls that did not have a corresponding bobbin signal. Those +Pt indications that did not have a corresponding bobbin signal were in fact found to have bobbin signals at the elevations corresponding to the +Pt call, however, the amplitude was <0.20 volts in 130kHz. The bobbin data was reanalyzed with no voltage cutoff and all newly reported FSD signals from this evaluation were reviewed against the first ISI by bobbin of this tube. This reanalysis did not identify any additional non-ding freespan ODSCC indications but a misclassified FSD was found. This indication (R7 C1 12) was judged to be the most significant indication. Based on the observation of a +Pt SAI call in R7C1 12, a second reanalysis of the bobbin data for freespan axial ODSCC was performed. This reanalysis considered all tubes, not just those tubes with new FSD signals that were reported as part of the reanalysis. This review was performed manually with no voltage cutoff and used a history review to the first ISI of this tube. Three additional, low voltage, shallow indications were reported as part of this analysis. Therefore, the final bobbin data reanalysis is summarized as a complete review of all bobbin data with no 130 kHz reporting threshold, with a history review to the first ISI of 15 of 46
SG-SGDA-03-03-NP that tube, for any FSD signal.
Figure 14 provides a PoD plot for the bobbin coil. This plot is developed by assigning a maximum depth (based on +Pt amplitude) to all reported +Pt indications. All +Pt indications were eventually reviewed to determine if a bobbin signal was present. If a bobbin signal was present, a value of 1 was assigned. If no bobbin signal was present, a value of 0 was assigned. A LogLogistic fit was then applied to the data to develop a PoD curve dependent upon flaw maximum depth. This evaluation does not use production analysis reports, but is designed to identify the detection capabilities of the bobbin coil. As seen from Figure 14, at a PoD of 0.95, the corresponding flaw maximum depth is 44%TW. The final bobbin reanalysis performed for the 1RF09 outage compared a 1RF09 DFI report against the first inservice inspection bobbin data for this signal to determine if change had occurred.
Since the original ADS screening criterion used a 130 kHz bobbin amplitude of 0.20 volts, all 130 kHz indications with an amplitude of >0.20 volts are assumed to be identified as a FSD signal.
Subsequent review to the first ISI will result in a DFI report. Therefore, the functional PoD of bobbin signals with a 130 kHz amplitude of >0.20 volts is 1. Using 130 kHz amplitude versus maximum depth correlation provided in Figure 8 the associated maximum depth is 55% using the mean correlation, 62% at the upper 90% probability, 50% confidence. Therefore, a functional PoD of 0.95 will provide for detection of indications between maximum depths of 44% and 55%. To estimate the functional PoD for the final bobbin reanalysis, results of a detection test performed during the outage will be utilized. Since the bobbin indication on RI 1 C42 at H5 +10.63" was perceived to have significant depths based on the phase analysis without analyst reporting of the indication, this tube was reinserted into the analysis program using a different tube identification. Detection results for 8 analysts were considered. All 8 analysts identified the indication in question (H5 +10.63", the indication pulled and burst tested in the lab at 8177 psi) for a functional PoD of 1. Figure 14 plots the results of this test for the 9 indications reported for tube R1 1 C42. The maximum depths used to develop the Figure 14 PoD curve were adjusted so that the PoD curve provided a PoD that bounds the results of the PoD test. This curve provides a 0.95 PoD for a maximum depth of 50%TW. Therefore, a 50%TW indication will be considered as the upper bound flaw depth that could be postulated to be left in service. The adjusted PoD curve is also provided in Figure 14. For the above analysis regarding depth, the 95% cumulative probability growth is 0.14 volts in 130 kHz, or approximately 13%TW at the amplitudes associated with this depth. Therefore, the upper bound maximum depth assumed at EOC-10 is 63%TW. For a maximum to average depth ratio of 1.4 for freespan indications, the corresponding average depth is 45%. For assessment of structural integrity, an infinitely long flaw with an average depth of 45% was assumed. Using the lower 90% probability, 50% confidence flow stress for 3/4" OD x 0.043" nominal wall Alloy 600 tubing, the predicted burst capability is 6638 psi. Therefore, structural integrity at EOC-10 is confirmed. For comparison purposes only, an infinitely long flaw with an average depth of 63%TW was used for calculation of burst capability. Using the lower 90% probability, 50% confidence flow stress value, predicted burst pressure is 4623 psi, which is greater than the Comanche Peak 3 times normal operating pressure differential.
The statistically based assessment utilized the 95% cumulative probability growth value for predicting the EOC-10 condition. The growth allowance included is 13%TW per cycle. History review of the R7 C 112 indication shows that a precursor signal was present in the 1RF07 (1999) data.
Based on the amplitude response at 1RF07, the estimated depth is 66% from the 130 kHz bobbin amplitude and 72% from the 300 kHz bobbin amplitude. Therefore, the growth allowance used is reasonable when the 2002 maximum estimated depth of R7 C 112 of about 82%TW is considered.
However, if it is assumed that the maximum depth of the R7 Cl 12 indication at 1RF06 (no detectable 16 of 46
SG-SGDA-03-03-NP signal) is consistent with the 1RF09 +Pt calls devoid of a corresponding signal (30 to 40%TW), an upper bound growth rate of about 17%TW per cycle is developed. If the idealized PoD curve of Figure 14 is used at the 0.05 PoD level, a bounding growth rate of 18%TW per cycle is developed.
For conservatism, a bounding growth of 20%TW per cycle will be used. Using the maximum depth of 50%TW at a PoD of 0.95, the estimated maximum depth at EOC-10 is then 70%TW, with an associated average depth of 50%. Again for an infinitely long flaw, the predicted burst capability is 6084 psi. As maximum depth at EOC-10 is estimated to be 70%TW, no leakage contribution at SLB conditions is postulated for freespan axial ODSCC.
As the freespan ODSCC operational assessment has been performed using multiple methods and approaches, Table 5 is provided to summarize the results. As seen from Table 5, all EOC-10 predicted burst capabilities provide margin against the 3AP performance criterion, and therefore structural integrity is provided at EOC-10.
Figure 15 provides a basis for use of the +Pt amplitude versus depth correlation for estimation of flaw maximum depths in the PoD curve development. This plot was developed by selecting pulled tube flaws for 11/16", 3/4", and 7/8" OD tubing. TSP axial ODSCC, freespan axial ODSCC, and sludge pile axial ODSCC flaws were used. The as-reported depth profiles from phase analysis and depth profiles using the +Pt amplitude versus depth correlation (both mean correlation and upper 90%
probability, 50% confidence relation) were then plotted against the destructive examination results.
This comparison showed that the maximum depth from phase tended to overestimate (grossly) the maximum depth of shallow flaws and tended to underestimate the maximum depth of deep flaws.
The amplitude sizing results showed that the upper 90% probability, 50% confidence relation produced a slope of approximately 1, with a y-intercept of -10% (NDE%TW on x-axis, DE%TW on y-axis). The amplitude sizing results showed that the mean correlation produced a slope of approximately 1, with a Y-intercept of (+)2%. The Rý value for both regressions ranged from 0.77 to 0.73 for 25 data points, indicating a valid correlation per the EPRI Tube Integrity Assessment Guideline. As a result of this comparison, the mean +Pt amplitude versus maximum depth correlation was selected for estimating the maximum depth of the reported indications.
Table 5 Summary of Freespan ODSCC EOC-10 Predicted Burst Capabilities Method BOC assumed Growth EOC predicted Flow EOC-10 condition condition Stress Burst Pressure (psi) la (1) 62% max depth 12%TW per cycle 74% max depth, 1.75" 134 ksi 5986 lb (2) 65% max depth 12%TW per cycle 77% max depth, 1.75" 134 ksi 5772 2a 0.20 volts (1) 0.14 volts 0.34 volts 134 ksi 5548 2b 0.30 volts (2) 0.20 volts 0.50 volts 134 ksi 4788 3
50% max depth 13% TW per 63% max depth, 134 ksi 6638 cycle infinite length 4
50% max depth 20%YTW per 70% max depth, 134 ksi 6048 cycle infinite length (1): Based on 130 kHz bobbin amplitude (2): Based on 300 kHz bobbin amplitude Method 1 uses a correlation of bobbin amplitude to maximum depth for estimation of BOC flaw depths and growth 17 of 46
SG-SGDA-03-03-NP Method 2 uses a correlation of bobbin amplitude to predicted burst capability Method 3 uses a bobbin PoD at 0.95 to define a BOC maximum depth 4.1.5 Ding ODSCC Operational Assessment With the exception of R41 C71 SG2, the ding ODSCC at Comanche Peak IRF09 performed similar to all other observed incidents of ding ODSCC in preheater SGs. That is, the growth (observed by 130 kHz differential phase change) was small.
Each of the confirmed ding ODSCC indications had a +Pt phase angle in the ID plane. This phenomenon was observed in the qualification data for flaws with <70%TW maximum depth. Each of the ding flaws with ding amplitudes of <5V had a 130 kHz bobbin phase that showed some rotation (i.e., phase angle <1800) in the 2001 data. Since detection is not likely for flaws less than about 50%TW regardless of the ding amplitude, the maximum depth growth rate of IRF09 ding flaws is likely bounded by about 20%TW. Length evaluation of the 1RF09 ding flaws indicates that the maximum reported length was approximately 0.30", with only a small variation in the reported ding ODSCC lengths. The variance in ding amplitudes and observed phase rotation suggests that the ding ODSCC flaws initiate and grow along the initiated front without corresponding length growth. The qualification data shows that the ding flaws only extended outside of the ding when an additional external stress riser was added. Thus for ding flaws that behave in the typical mode, EOC-10 postulated flaw lengths are expected to be significantly less than the 100%TW critical flaw length with maximum depths less than about 80 to 90%TW. Therefore, structural and leakage integrity at EOC-10 conditions will be provided. A similar result is obtained if a statistically based POD curve developed using the data contained in Reference 8 is used. At a POD of 0.95, the associated maximum depth is approximately 75%TW, for dings up to 5 volts. At EOC-10, the maximum depth is postulated to be 95%TW. Leakage integrity is expected at a maximum depth of 95%TW.
The growth performance of R41 C71 was clearly different from the rest of the ding ODSCC population. Figure 12 plots the 130 kHz phase change for all reported ding flaws comparing the 2002 and 2001 130 kHz phase responses. Figure 12 shows that only 2 indications had a 130 kHz bobbin phase change of greater than 200. These two indications are represented by R41 C71 and another indication (R25 C30 SG3). The other indication was reported in a <1 volt ding. Once ODSCC initiated in this ding, the limited ding influence would result in significant phase change for only moderate ODSCC depth changes. The remaining 1RF09 indications were located in dings up to 6.2 volts, and therefore would result in lesser amounts of phase change due to the combination of the ding and flaw vectors. Since the ding amplitude of R41 C71 was estimated at 1.7 volts, the amount of phase change for this tube is significantly different from the rest of the 1RF09 ding ODSCC population, and significantly different from the ding flaws reported at other plants.
The changes made to the bobbin reporting criteria for the 1RF09 inspection were designed to identify the 1RF07 precursor signal for R41 C71. Therefore, if indications similar to R41 C71 are present in the Comanche Peak SGs, they would have been reported in the bobbin reanalysis program. Also, all FSD signals reported in the U-bend region of the Comanche Peak SGs at 1RF09 were +Pt inspected.
Therefore, it is not reasonable to assume that an indication similar to R41 C71 in 2001 is currently present in the Comanche Peak Unit 1 SGs.
4.1.6 Axial PWSCC at the Top of Tubesheet Expansion Transition Operational Assessment 18 of 46
SG-SGDA-03-03-NP Structural integrity of axial flaws is established based on reported NDE length and depth.
During the 1RF09 inspection, 2 axial PWSCC indications were reported at the expansion transition, one in SG2, one in SG3. The most significant of these was a 1.75 volt, 0.16" long indication, reported from the 300 kHz +Pt channel. Use of the 80 mil high frequency coil indicates 3 closely spaced axial flaws with a maximum reported depth of 60%TW. Review of the IRF08 data indicates a 1.12 volt, 0.13" long indication was present (300 kHz +Pt). As the +Pt coil field width is such that the three indications reported were combined into one signal, use of the +Pt amplitude versus maximum depth relation would be expected to provide a conservative estimate of flaw depths. At 1.75 +Pt volts, the expected depth is [
]ac e. At 1.12 volts, the expected depth is [
]ac e, using the upper 95% probability, 50% confidence relation. Therefore, the growth in depth of this indication is approximately 16%TW for Cycle 9. Figure 16 presents results of a depth sizing evaluation for axial PWSCC flaws relating +Pt amplitude to maximum depth from destructive examination.
The second indication had a +Pt amplitude of only 0.42 volts and length of 0.16". At such low volts the +Pt depth response should be in the range of 40 to 45%TW. Significant depths (-100%TW) were reported, suggesting that the depth sizing from phase is unreliable. Pulled tube data shows that an axial PWSCC indication in the expansion transition with total length of 0.19" and 100%TW depth over the length of the flaw had a +Pt amplitude of 6.3 volts. Therefore, it is not likely that the depth of this indication approaches 100%TW. Profiling using the 600 kHz +Pt channel reported similar depths, but the flaw amplitudes were less than the 300 kHz channel. For an ID flaw, the higher frequency channels should produce larger flaw amplitudes. As with OD signals, weak ID signals can also be affected by the carbon steel response of the tubesheet. However, for an ID flaw, the carbon steel influence would likely result in rotation towards the OD plane, giving overestimates of depth.
The most conservative profile for this tube was obtained using the 80 mil high frequency +Pt coil.
This profile also reported flaw lengths that were approximately 1.5 times longer than the 300 kHz +Pt coil response. Thus this profile was used for the integrity evaluation. A history review of the 1RF08 data for this tube indicates no detectable degradation.
Reference 9 indicates that for a large population of axial PWSCC indications in hardroll expansion transitions, that for flaw lengths > 0.20", that the upper bound length growth was constant at 0.06" per 12 month cycle. Therefore, an 18 month basis growth of 0.09" will be applied for the operational assessment. The reported flaw lengths from the 300 kHz +Pt channel for each of the 1RF09 indications was 0.16". The roll expansion transition length is bounded by about 0.25". It is unlikely that flaw progression outside of the roll expansion transition would be observed. Therefore, the operational assessment will use a beginning of cycle flaw length of 0.25". The EOC-10 flaw length is then estimated at 0.33", which is less than the 100%TW critical flaw length of 0.43". Therefore, structural integrity is expected to be provided at EOC-10 for axial PWSCC indications at the expansion transition.
If a loglogistic POD curve is developed using the data of ETSS 20511.1, the maximum depth associated with a POD of 0.95 is 54%TW. From above, a conservatively established maximum depth growth of 16%TW for Cycle 9 is established. Therefore, maximum postulated depth at EOC-10 is approximately 70%TW. Thus, leakage contribution at SLB conditions for axial PWSCC indications is not expected at EOC-10.
4.2 Operational Assessment of Wear Mechanisms 19 of 46
SG-SGDA-03-03-NP 4.2.1 Tube Wear at AVBs, Preheater Baffles, and Due to Loose Parts/Foreign Objects Tube wear due to foreign object interaction was reported in SGs 1, 3, and 4. The tubes with wear indications were located at the top of tubesheet and in upper bundle regions. In all cases, the wear mechanism could be tracked to the previous inspection. These indications were sized using the EPRI volumetric standard and guidance provided in ETSS 21998.1. The deepest and longest indication was reported at 28%TW, 0.313". Using depth sizing uncertainty associated with ETSS 21998.1, a 28%TW indication could suggest a depth of 42.4%TW at the upper 90% probability, 50%
confidence. As growth rates of foreign object wear mechanisms are dependent upon the object geometry and location within the tube bundle, growth rates are judgmental. All IRF09 foreign object wear indications had precursor signals in a history review of the 1RF08 data, thus, the growth rates are judged to be less than 28%TW. A growth rate of 21%TW per cycle will be assumed based on presence of a precursor signal in 1RF08. Thus the maximum depth foreign object wear scar assumed for EOC-10 is 63.4%TW. The longest reported foreign object wear scar length at 1RF09 was 0.313".
Previous evaluations performed by Westinghouse have indicated that the +Pt coil overestimates the length of foreign object wear scars. Therefore, it is conservative to use the reported flaw lengths froma 1RF09. At 0.313" length, the associated depth that provides burst capability of 3APNomOp, calculated using the uniform thinning equation ofNUREG/CR-0718 is approximately 80%TW. Therefore, structural integrity of postulated foreign object wear scars is expected to be provided at EOC-10.
Tube wear at non-expanded baffles represents a low growth mechanism. The largest reported depth at 1RF08 was 43% TW. This indication was also the largest reported depth at 1RF07 of 37%. The largest reported depth at 1RF09 was 41% TW, in SG 4. The growth associated with this indication was 6% TW for Cycle 9, 5% for Cycle 8. One additional repairable indication was reported in SG 2 at 40%TW. The Cycle 9 growth for this indication was 13%, with no growth reported for Cycle 8.
The average and 95% confidence growth rates for all baffle wear indications combined for Cycle 9 is 2.14% and 6.45%, respectively. The 95% CPDF growth rate for baffle wear indications is 5%.
Therefore, an upper bound growth of 6.45% will be used for the operational assessment. The baffle wear growth statistics were conservatively adjusted by setting negative growth values to 0 in the average growth calculation. Using the total sizing information of ETSS 96004.3 at the upper 90%
probability, 50% confidence level suggests an indication depth of 51.2%TW for a reported depth of 39%TW left in service at BOC-10. At EOC-10, the postulated depth is 57.7%TW, which is less than the structural limit using lower tolerance limit material property values of 68.6%.
The maximum AVB wear depth reported was 33% TW in SG 3. The growth associated with this indication was 1% TW. The largest reported AVB wear growth reported was 2% TW. As only 12 AVB wear indications were reported with corresponding depth values in 1RF08, a statistical growth evaluation cannot be performed. Instead, a bounding growth of 15% will be used in the operational assessment. Based on ETSS 96004.3, the suggested indication depth for a reported depth of 33%TW using the total sizing uncertainty at 90% probability, 50% confidence is 43%TW. The maximum estimated depth at EOC-10 is then 58%TW, which is well below the structural limit of 75%
determined using lower tolerance limit material property values. Therefore, structural integrity will be provided at EOC-10 for AVB wear indications.
In summary, structural and leakage performance criteria are satisfied at EOC-09 conditions for preheater baffle wear and AVB wear.
20 of 46
SG-SGDA-03-03-NP 4.3 Special Considerations Westinghouse letter LTR-SGDA-02-246 addresses preventive plugging of tubes potentially susceptible to high cycle fatigue at the top TSP (GL 88-02 concern) for the 1.4% uprated condition.
This letter concludes that preventive repair is required for several tubes if the steam pressure drops below 959 psia. Based on Reference 10, the current minimum steam pressure for all 4 loops is 955 psig (-969.7 psia) in loop 1. Therefore, no action is required. The actual steam pressure at the U bend region is higher than the reported value of 955 psig due to line losses between the sensing point and the U-bend region. The steam pressure of 959 psia is coincident with an average steam generator tube plugging level of 10%. Current average tube plugging level is approximately 3% average included flow restriction effects due to sleeving.
5.0 Pulled Tube Examination Results Two tubes were pulled during the IRF09 outage. The pulled tubes were R1 1 C42 hot leg and R25 C30 cold leg. Ri1 C42 was pulled to determine the burst pressure of the freespan axial ODSCC indication at H5 +10.63" and to help to define bobbin coil detection capabilities. R25 C30 was pulled to investigate the ding ODSCC reported on the cold leg.
Material properties for Ri1 C42 were determined from a tensile test on a section of removed tube.
The room temperature yield strength was 54.2 ksi and the ultimate strength was 100.8 ksi, for a two times flow stress value of 155 ksi. The CMTR data for this tube indicates a yield strength of 53 ksi, ultimate strength of 98 ksi, and two times flow stress of 151 ksi.
Upon receipt a 12" long section with the indication at 10.63" above H5 centered in the section was burst tested. The room temperature laboratory burst pressure was 8177 psi. The burst testing procedure included 2 minute hold points at each 500 psi pressure increment.
The burst face examination indicated that the maximum depth of ODSCC at the center of the burst opening was 48%TW. ODSCC existed at low levels (5 to 20%TW) over the entire length of the section. Figure 13 presents a plot of the depth profile from destructive examination for the section in question. Figure 13 also includes the NDE based depth profiles using the depth reports from phase and the depth reports based on a relationship between +Pt volts and maximum depth. As seen from Figure 13, the depth reports from phase overestimated the true depth while the depth based on +Pt amplitude show excellent agreement with destructive examination. Eddy current indications were also noted in the field at approximately 12.2 and 14.7" above H5. The maximum depth at these areas were 55% and 56%TW respectively, however, the flaw lengths were short. For each of these flaws the length with depth >20%TW was only 0.25".
6.0 Conclusion Based on the evaluation provided herein, it can be concluded that structural and leakage integrity pursuant to NEI 97-06 will be provided for the Comanche Peak Unit 1 SGs following the Cycle 10 operating period. Table 6 presents a summary of the predicted EOC-10 burst capabilities for each of the degradation mechanisms observed at the Comanche Peak 1RF09 outage.
7.0 Benchmarking of Cycle 9 Operational Assessment 21 of 46
SG-SGDA-03-03-NP Circumferential ODSCC at Expansion Transition:
The Cycle 9 operational assessment considered both circumferential flaw amplitude at EOC-9 and PDA. The maximum projected flaw amplitude for 1RF09 using the 95% CPDF flaw amplitude for 1RF08 and 95% CPDF amplitude growth is 0.46 volts. For 1RF09, the 95% CPDF flaw amplitude was 0.27 volts, and only one indication was reported with an amplitude >0.46 volts.
The 1RF09 predicted burst capability at 95% probability, 50% confidence was estimated at 4337 psi.
Using the PDA distribution of Figure 3 adjusted at the upper 90% probability, 50% confidence level, the 95% CPDF PDA is 52%. The corresponding burst capability using lower tolerance limit material properties is 5969 psi. Therefore, the methodology applied for the circumferential ODSCC operational assessment is considered conservative.
Axial ODSCC at Expansion Transition:
The Cycle 9 operational assessment postulated an upper bound flaw length of 0.37" at EOC-9. The longest reported axial ODSCC indication at the expansion transition was 0.30" based on amplitude response, 0.27" based on phase response. Using the axial flaw length uncertainties defined by the degradation assessment, a flaw length of 0.30" could be expected to represent a true flaw length of 0.40". Therefore, the predicted flaw length of 0.37" compares well with the maximum adjusted 1RF09 flaw length of 0.40".
8.0 Comanche Peak 1 In Situ Pressure Testing History Table 7 presents a summary of the in situ testing history at Comanche Peak Unit 1. The flaw parameters for the tested circumferential ODSCC indications are consistent for each inspection, suggesting that the upper bound flaw severity has not changed over at least 4 inspections.
No leakage or burst was reported for any circumferential ODSCC in situ pressure test at Comanche Peak Unit 1RF09 or any other previous outage. No leakage or burst was reported for any freespan axial ODSCC in situ pressure test at Comanche Peak 1RF09. No leakage or burst was reported for any ding axial ODSCC indications in situ pressure tested at 1RF08 and 1RF09 with the exception of R41 C71 in SGB.
22 of 46
SG-SGDA-03-03-NP 9.0 References
- 1.
SG-01-02-004, "Comanche Peak Steam Electric Station Unit 1 Steam Generator Degradation Assessment 1RF08 Refueling Outage", February 2001 (Westinghouse Proprietary)
- 2.
SG-01-03-003, "Performance Evaluation of Segment Method for Circumferential ODSCC Sizing in Hardroll Expansion Joints", March 2001 (Westinghouse Proprietary)
- 3.
SG-01-03-002, "Circumferential ODSCC Profiling Method for Hardroll Expansion Joints",
March 2001 (Westinghouse Proprietary)
- 4.
SG-01-01-001, "Site Specific Eddy Current Noise Evaluation Methodology Relating to SG Tube Integrity", January 2001 (Westinghouse Propreitary)
- 5.
CN-SGDA-02-93, "Circumferential ODSCC Sizing Uncertainties", April 2002 (Westinghouse Proprietary)
- 6.
EPRI TR-107621R1, "Steam Generator Integrity Assessment Guidelines", March 2000
- 7.
EPRI TR-107569-V1R5, "PWR Steam Generator Examination Guidelines", September 1997
- 8.
SG-SGDA-02-36, "Comanche Peak Steam Electric Station Unit 1 Steam Generator Degradation Assessment 1 RF09 Refueling Outage", September 2002 (Westinghouse Proprietary)
- 9.
STAC - A new code for statistical analysis of cracks in SG tubes, NUREG/CP-0154, Proceedings of the CNRA/CSNI Workshop on Steam Generator Tube Integrity on Nuclear Power Plants, November 1995
- 10. Email from S. Swilley to W Cullen, dated 1/21/03
- 11. EPRI TR-107197, Depth Based Structural Analysis Methods for SG Circumferential Indications", November 1997 23 of 46
SG-SGDA-03-03-NP 24 of 46 Table 6 Comanche Peak EOC-10 Summary of Structural and Leakage Integ at EOC-10 Mechanism Minimum Projected Structural Postulated EOC-10 Structural Integrity Leakage at Integrity Parameter Parameter SLB Conditions Circ ODSCC at TTS 6700 psi 3855 psi 0
Axial ODSCC at TTS 5856 psi 3855 psi 0
Axial ODSCC in 4788 psi 3855 psi 0
Freespan Axial PWSCC at TTS 0.33" 0.43" 0
AVB Wear 58%TW 75%TW 0
Baffle Wear 58%TW 68.6%TW 0
SG-SGDA-03-03-NP Table 7 CPSES 1RF09 In Situ Testing Sum ary Tube SG Degradation Location Flaw Max Depth
+Pt Volts Leak Test Proof Test Leakage Burst Mode Length (NDE)
Pressure (2)
Pressure R41 C55 1
Axial ODSCC HI0 +38" 0.10"
-70%
0.93 4070 4070 No No R41 C75 1
Axial ODSCC CIO +38" 0.23"
-70%
0.48 4070 4070 No No R42 C59 1
Axial ODSCC AV3 +1.6" 0.27"
-70%
0.52 4070 4070 No No R45 C24 1
Axial ODSCC AV3 +1.7" 0.20"
-70%
0.43 4070 4070 No No R5 C70 2
Circ ODSCC HTS -0.29" 3600 61%
0.18 2970 4375 No No R7 C73 2
Cire ODSCC HTS -0.29" 3300 76%
0.32 2970 4375 No No Rll C42 2
Axial ODSCC H5 +10.63" 1.63" 64%
0.21 2841 N/A No N/A R41 C71 2
Axial ODSCC AV3 +26" 0.91" 100%
6.5 2150 N/A Yes (1)
N/A R44 C83 2
Axial ODSCC AV2 +27" 0.25"
-70%
0.45 4070 4070 No No R7 C17 3
Axial ODSCC H5 +11.73" 1.14" 68%
0.26 4070 4070 No No R4 C51 3
Axial ODSCC H9 +9" 0.89" 71%
0.24 2841 4070 No No R2 C77 3
Circ ODSCC HTS -0.31" 2700 60%
0.38 2970 4375 No No R38 C77 3
Circ ODSCC HTS -0.25" 2700 76%
0.42 2970 4375 No No R7 C90 3
Axial ODSCC H3 +29.2" 2.81" 60%
0.26 2841 4070 No No R23 C90 3
Cire ODSCC HTS -0.29" 1200 76%
0.44 2970 4375 No No R36 C93 3
Circ ODSCC HTS -0.14" 2100 82%
0.22 2970 4375 No No R7 C112 3
Axial ODSCC H8 +8.56" 2.88" 62%
0.81 2841 4070 No No R32 C65 4
Circ ODSCC HTS -0.46" 3300 76%
0.56 2970 4375 No No R4 C77 4
Circ ODSCC HTS -0.25" 3300 48%
0.26 2970 4375 No No CPSES 1RF08 In Situ Testing Sum ary Tube SG Degradation Location Flaw Max Depth
+Pt Volts Leak Test Proof Test Leakage Burst Mode Length 91%E)
Pressure Pressure R18 C84 4
Circ ODSCC HTS -0.28" 2700 91%
0.19 2955 4395 No No R2 C72
,_4 Circ ODSCC HTS -0.02" 2700 42%
0.31 2955 4395 No No 25 of 46
SG-SGDA-03-03-NP CPSES 1RF07 In Situ Testing Summ ary Tube SG Degradation Location Flaw Max Depth
+Pt Volts Leak Test Proof Test Leakage Burst Mode Length (NDE)
Pressure Pressure R22 C89 4
Circ ODSCC HTS -0.23" 3390 69%
0.23 2925 4385 No No R32 C77 4
Circ ODSCC HTS -0.14" 2920 63%
0.32 2925 4385 No No R38 C78 4
Circ ODSCC HTS +0.11" 2650 71%
0.17 2925 4385 No No CPSES 1RF06 In Situ Testing Summary (limiting indications)
Tube SG Degradation Location Flaw Max Depth
+Pt Volts Leak Test Proof Test Leakage Burst Mode Length Pressure Pressure RI C69 2
Circ ODSCC HTS +0.12" 2960 61%
0.43 2925 4315 No No RI C73 2
Circ ODSCC HTS -0.17" 3260 67%
0.47 2925 4315 No No RI C95 2
Circ ODSCC HTS -0.32" 3370 64%
0.44 2925 4315 No No R3 C96 2
Circ ODSCC HTS -0.25" 3500 71%
0.38 2925 4315 No No R3 C103 2
Circ ODSCC HTS-0.14" 3600 71%
0.43 2925 4315 No No Notes:
- 1. R41 C71 leaked at a maximum rate of 0.03 gpm at pressure differential of 1439 psi (normal operating temperature adjusted). Leak test was stopped at 2150 psi due to leakage exceeding pump capacity of 2.6 gpm. Burst could not be established. Predicted burst pressure is approximately 2727 psi.
- 2. All axial ODSCC tests were conducted using full tube setup, thus leak and proof test pressures are equal.
- 3. All maximum depths based on phase analysis for most reliable depth points.
26 of 46
SG-SGDA-03-03-NP 27 of 46 Table 8 1RF09 Axial ODSCC in Dings Pre and Post In Situ +Pt Parameters Pre In Situ Post In Situ SG Row Col Location Elevation 130 kHz Volts 130 kHz Phase
+Pt Volts Phase (1)
+Pt Volts Phase 1
41 55 H10
+37.97 1.15 1660(2) 0.93 60 1.01 90 1
41 75 CIO
+37.90" 0.51 1520 0.48 50 0.62 100 1
42 59 AV3
+1.9" 0.58 1550 0.52 210 0.55 260 1
45 24 AV3
+1.7" 0.24 610 0.43 240 0.42 370 1
49 74 AV4
+2.84" 0.40 1250 0.41 350 N/A N/A 1
49 43 AV4
-0.82" 0.85 1650 (3) 0.34 350 N/A N/A 1
32 74 HI
+5.12" 0.35 1300 0.25 240 N/A N/A 1
41 77 CIO
+37" 0.58 1450 0.54 170 N/A N/A 1
41 79 C1O
+38" 0.54 1530 0.59 80 N/A N/A 1
41 94 C1O
+38" 0.77 1500 0.67 140 N/A N/A 1
41 95 C1O
+27.6" 0.77 1450 0.76 100 N/A N/A 2
25 30 C7
+23.4" 0.20 820 0.27 160 N/A N/A 2
44 83 AV3
-2.31" 0.45 1130 0.45 390 0.53 630 2
44 83 AV3
-0.28" N/A (4)
N/A 0.33 40 0.29 180 2
33 100 H1
+13.6" 0.65 134 0.63 190 N/A N/A 4
41 85 AV4
+11" 0.21 670 0.21 450 N/A N/A Note:
- 1) Ding flaw +Pt phase is often in ID plane for shallow OD flaws. Bobbin response indicates classic ODSCC influence.
- 2) R41 C55 ding amplitude is 6.2 volts, thus bobbin technique is not applicable for detection
- 3) Due to proximity with AVB, 130 kHz channel could not be used. Mix channel data is provided and shows reportable phase rotation.
- 4) Due to proximity with AVB, 130 kHz channel could not be used. Mix channel data shows a ding.
SG-SGDA-03-03-NP Table 9 Axial ODSCC in Freespan in Absence of Dings: Pre and Post In Situ +Pt Parameters Pre In Situ Post In Situ SG Row Col Location Elevation Volts Depth Length Volts Depth Length 2
11 42 H3
+2.16" 0.06 44%
0.69" 0.08 44%
0.89" H3
+3.14" 0.09 45%
0.26" 0.12 58%
0.33" H3
+7.34" 0.17 43%
0.56" 0.19 41%
0.59" H3
+8.92" 0.06 65%
0.20" 0.07 49%
0.20" H5
+10.63" 0.21 61%
1.63" 0.26 61%
1.69" H5
+12.46" 0.17 56%
0.39" 0.20 55%
0.39" H5
+14.64" 0.11 71%
0.49" 0.15 61%
0.49" 2
11 94 H1
+13.6" 0.14 57%
0.20" N/A N/A N/A 3
4 51 H9
+8.9" 0.24 61%
0.89" 0.34 46%
0.89" H9
+20.2" 0.13 19%
0.58" 0.17 17%
0.62" C7
+37.5" 0.08 20%
0.62" 0.10 N/A N/A C7
+37.74" 0.05 46%
0.22" 0.11 N/A N/A C7
+38.43" 0.09 29%
1.24" 0.14 N/A N/A 3
7 17 H5
+11.73" 0.26 64%
1.14" 0.40 54%
1.20" C8
+25.90" 0.18 51%
0.41" 0.23 41%
0.48" C8
+28.41" 0.04 54%
0.16" 0.07 34%
0.32" 7
90 H1
+14.93" 0.14 53%
0.54" 0.22 36%
0.65" H1
+15.3" 0.03 10%
0.21" N/A N/A N/A H1
+16.31" 0.04 34%
0.30" 0.05 41%
0.38" H1
+20.29" 0.05 38%
0.33" N/A N/A N/A H1
+22.35" 0.03 42%
0.21" N/A N/A N/A HI
+22.99" 0.03 37%
0.13" N/A N/A N/A H1
+27.07" 0.05 35%
0.17" N/A N/A N/A HI
+28.31" 0.09 24%
0.20" N/A N/A N/A H1
+28.62" 0.05 54%
0.14" N/A N/A N/A H3
+5.26" 0.06 33%
0.21" N/A N/A N/A H3
+24.65" 0.10 69%
2.30" N/A N/A N/A H3
+27.09" 0.17 41%
1.10" 0.20 44%
1.19" H3
+29.21" 0.26 60%
1.50" 0.36 58%
1.66" 28 of 46 3
SG-SGDA-03-03-NP 44%
1 0.36" 1
0.13 I
N/A I
N/A 29 of 46 69%
1 0.29" 1
0.07 1
N/A I
N/A C8
+6.71" 0.08 C8
+34.48" 0.10 3
7 112 H8
+8.56" 0.81 60%
2.70" 1.83 61%
2.77" Note: Depth reported by phase at point of maximum +Pt volts. Elevation reported at point of max volts
SG-SGDA-03-03-NP Table 10 Comanche Peak IRF09 FSD Flaw Bobbin Data Summary SG Row Col LOCN 42 H3 +2.2 42 H3+3 1 42 H3 +7.4 42 H3 + 8 9 42 H51+106 42 H5 +12 4 42 H5 +14.7 42 C9 0
9 3 42 C9 +10 1 42 C9 +10 6 42 C9 +12 7 17 H5 +12 3 17 C8 +4 17 C8 +26 17 C8 +28 4 112 H8 +8.7 90 H1 +14 8 90 H1 +15 3 90 H1 +16 3 90 HI +20 3 90 Hi +22.4 90 HI +23 90 H1 +26 3 90 Hi +27.1 90 Hi +28.3 90 H1 +28 6 90 H3 +5 3 90 H3 +24 7 90 H3 +27.1 90 H3 +29 2 90 C8 +6.7 90 C8 +8 6 90 C8 +11.3 90 C8 +34 5 51 H9 +8.9 51 H9 +20 2 51 C7 +37 5 51 C7 +37.7 51 C7 +38 4 94 HI +13 6
. POST In Situ +Pt Voltages 1RF09 1RF09 1RF09 011RF08 1RF07
+Pt
+Pt 300 300 P4:130 P4:130 300 300 P4"130 P4 130 300 300 P4.130 P4.130 VeIt
I nnth I Phe
VnIt
P!w*.*
006 056 009 026 017 039 006 02 021 163 017 039 0.11 0.33 008*
021 007*
031 0 06
- 022 0.1
- 0.31 026 1.14 NIA NIA 018 041 004 0.16 081 274 014 054 003 021 004 03 005 033 003 021 003 013 006 024 005 017 009 02 005 0.14 006 021 01 23 0.17 1.1 026 15 008 029 004 029 004 033 01 036 024 089 013 058 008 062 005 022 009 124 014 02 Vnlfk Ph*¢:
Vnlf.*
Ph
JnItq I
\\IrIf*
Ph*
Int*
NOD NOD Volts__
Lenrih 1
hs ols Pae.ot.hse Vls Phs ot I
Pas ols hse Vot NDD 111 107 93 94 63 172 77 126 118 83 94 118 119 NDD 62 78 NDD NDD NDD 62 NDD 43 NDD NDD NDD NDD 22 31 103 137 NDD NDD 101 34 45 NOD NDD 55 83 NOD 015 85 033 92 01 84 021 64 035 68 036 129 012 47 0.12 97 011 67 0.12 54 034 73 019 77 028 82 NOD 072 58 015 48 NOD NOD NOD 007 83 NOD 023 47 NOD NOD NOD NOD 013 42 018 40 019 72 011 63 NOD NOD 015 73 03 41 024 45 NOD NOD 013 54 021 62 0.11 02 0 08 016 0 27 011 011 0 04 0 03 011 0 25 012 02 0 48 012 0 08 013 0.12 012 0.13 0 09 0.14 0.19 0.18 01 0 22 NOD NOD 125 NOD 80 24 168 NOD 125 NOD NOD 012 75 009 NOD 018 56 018 024 17 0.14 029 140 012 NOD 01 105 003 120 012 62 007 64 018 62 0.17 146 NOD 72 112 NOD NOD NOD NOD NOD 28 NOD NOD NOD NOD NOD Poss 53 NOD 68 74 99 031 95 013 NDD 036 58 029 0.11 34 007 NOD NOD NOD NOD NOD 029 35 017 NOD NOD NOD NOD NOD Poss 0.19 45 015 NOD 008 51 007 01 85 005 0.11 62 007 1m7 n~v w*
R A9 NOD NOD NOD NOD 167 033 168 54 055 74 0.11 NOD 0.19 36 032 68 012 NDD 30 of 46 107 023 83 022 v
% JGMOd GV)
C 0
n 0
o 0
0 0
0O 0
m I
-r I
I
-9/28/02 12:00 9/28/02 8:00 9/28/02 4:00 co 9/28/02 0:00 0
V I
'Uu 0
9/27/02 20:00 9/27/02 16.00 ZN 0
"*.O 9/27/02 12:00 9/27/02 8:00 0
- L a
W 0 D0 o-9/27/02 4:00 2i92/°°° I
- 0.
9/27/02 20:00 0
c~)
S LEm9/26/02 20:00 d
'U°C
.E 2 L n,)
9/26/02 16:00 m
0 acm a 0 9/26/02 12:00 0
OC C) 0 9/26/02 8.000 I 9/26/02 4:00 S ill ll ll:
.... Ji ll l::
9/26/02 0:00 0D LO 0
1O 0
1O 0
1O
- 0)
LO 0
LO 0
co LO LO
- 1" co 0
CI I OdO
SG-SGDA-03-03-NP Figure 2 Comanche Peak 1RF09 Circ ODSCC +Pt Amplitude Distribution 180 160 140 120 100 80 60 40 20 0
oD M CD M
N U')
Mo '-
qt N-Mi' MV MD M N
LO MO
'T 0
CDC 0
0 N
N N
d c
6?
lq N
q-O t
"~z 0
f
)
f 6
66 6
6 6
6 6
0 66 6
C6 0
0 5
+Pt Volts Bin
[
= Frequency IRF09 S.-.
-Curmulative % 1 RF08 Currulative % I RF09 I..
>1 100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
.00%
32 of 46
SG-SGDA-03-03-NP Figure 3 Comanche Peak I RF09 Circ ODSCC PDA Distribution (maximum depths <40%TW assigned depth of 40%TW) 250 100.00%
90.00%
200 80.00%
70.00%
>- 150 60.00%
""-50.00%
100 40.00%
30.00%
50 20.00%
-10.00%
0 -, +.00%
'-)
0
",-O 0
N v
'D CO N
M CD C
-4 0
- ~
N NN N
M~
~
C')0 PDA% Bin SFrequency j.-in-Curmulatrve %
33 of 46
SG-SGDA-03-03-NP Figure 5 Comanche Peak Cycle 9 Circ ODSCC +Pt Voltage Growth 120 100 80 60 40 20 0
0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22 More
+Pt Voltage Growth Bin
=_ Frequency Currulatrve %
35 of 46 100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
.00%
SG-SGDA-03-03-NP Figure 6 Comanche Peak Cycle 9 Circ ODSCC PDA Growth 70 60 50 40 30 20 10 0
0 2
4 6
8 10 12 14 PDA Growth Bin 16 18 20 22 More
_ Frequency
-in-Cumulative %
36 of 46 L0 100.00%
90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
.00%
SG-SGDA-03-03-NP a,c,e Figure 7 37 of 46
SG-SGDA-03-03-NP Figure 8 McGuire Pulled Tubes 130 kHz Amplitude vs Max Depth (DE) with 1.0 volt 100%TW indication Added 100 90 80 70 60 50 40 30 20 10 0
0.01 X
0.1 130 kHz Bobbin Amplitude (volts) 38 of 46
SG-SGDA-03-03-NP Figure 9 Reevaluated January 1992 McGuire Data Max Depth (DE) vs Bobbin Amplitude 1
300 kI-z x
TBX Data Power (300 kHz) ---
- Power (TBX Data)....... Power (300 kHz Upper 90/50) 1 0.1 1
300 kHz Bobbin Volts 39 of 46 I-100 90 80 70 60 50 40 30 20 10 0
SG-SGDA-03-03-NP Figure 10 McGuire Pulled Tubes 130 kHz Bobbin Amplitude vs Calculated Pb / 3dP Actual FS 03 FS = 134
Lower 90/50 FS = 134 Rll C42 Lab Pb FS=134 Power (FS = 134)
Power (Actual FS) 35 3-2.5 aI.
",a 2
- a.
05 050 0.01 40 of 46 0.1 1
10 130 kHz Bobbin Ampliutde (volts)
SG-SGDA-03-03-NP Figure 11 McGuire R47C46 January 1992 Reevaluation 300 kHz Response ActuaIFS o
FS=134 0
RllC42PbLabFS=134 Lower 90/50 FS = 134
- - - Power (FS =134)
Power (Actual FS) 1 10 300 kHz Bobbin Amplitude 41 of 46 3
2.5 2
1.5
- g. 1.
0.5 0
0.1 100
SG-SGDA-03-03-NP Figure 12 Cycle 9 DNI Phase Change in 130 kHz 0
10 20 30 40 Bin 10 9
8 7
6 5
4 3
2 1
0 42 of 46
>1 C1
- 4)
ILL 100.00%
-- 90.00%
80.00%
70.00%
60.00%
50.00%
40.00%
30.00%
20.00%
10.00%
I-T
.00%
50 60 65 More Frequency a--- Cumulative %
SG-SGDA-03-03-NP a,c,e Figure 13 43 of 46
SG-SGDA-03-03-NP a,c,e Figure 14 44 of 46
SG-SGDA-03-03-NP Figure 15 45 of 46
SG-SGDA-03-03-NP Figure 16 Maximum Depth Performance: +Pt Volts versus Maximum Depth Axial PWSCC 1
o3 Volts Mean
-x--- Ideal Upper 90/50
Lower 90/50 Linear (Volts Mean) 0 10 20 30 40 50 60 70 80 90 NDE %TW 46 of 46 100 90 80 70 60 50 40 30 20 10 0
Ial 0
100 to TXX-03064 CAW-03-1608 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE
t~ginghouse Westinghouse Electric Company Nuclear Services P.O Box 355 Pittsburgh, Pennsylvania 15230-0355 USA U.S. Nuclear Regulatory Commission Direct tel: (412) 374-5282 Document Control Desk Direct fax: (412) 3744011 Washington, DC 20555-0001 e-mail: Sepplha@westinghouse.com Our ref: CAW-03-1608 March 12, 2003 APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE
Subject:
Transmittal of Westinghouse Proprietary Class 2 Documents:
"* SG-SGDA-02-43-P, "Comanche Peak Steam Electric Station IRF09 Outage Condition Monitoring Report and Preliminary Cycle 10 Operational Assessment" (Proprietary)
"* SG-SGDA-03-03-P, "Comanche Peak Steam Electric Station Unit I Cycle 10 Operational Assessment" (Proprietary)
The proprietary information for which withholding is being requested in the above-referenced reports is further identified in Affidavit CAW-03-1608 signed by the owner of the proprietary information, Westinghouse Electric Company LLC. The affidavit, which accompanies this letter, sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.790 of the Commission's regulations.
Accordingly, this letter authorizes the utilization of the accompanying affidavit by TXU Energy.
Correspondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW-03-1608 and should be addressed to the undersigned.
Very truly yours, H. A. ep,
anager Regulatory and Licensing Engineering Enclosures cc: S. J. Collins G. Shukla!NRR A BNFL Group company
CAW-03-1608 March 12, 2003 bcc: H.A. Sepp (ECE 4-7A) 1L, IA R. Bastien, IL, IA (Nivelles, Belgium)
L. Ulloa (Madrid, Spain) IL, IA C. Brinkman, 1L, IA (Westinghouse Electric Co, 12300 Twinbrook Parkway, Suite 330, Rockville, MD 20852)
RLE Administrative Aide (ECE 4-7A) I L, IA (letters w/affidavits only)
A BNFL Group company
CAW-03-1608 March 12, 2003 AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA:
ss COUNTY OF ALLEGHENY:
Before me, the undersigned authority, personally appeared H. A. Sepp, who, being by me duly sworn according to law, deposes and says that he is authorized to execute this Affidavit on behalf of Westinghouse Electric Company LLC ("Westinghouse"), and that the averments of fact set forth in this Affidavit are true and correct to the best of his knowledge, information, and belief:
H. A. Sepp, Manager Regulatory and Licensing Engineering Sworn to and subscribed before me this day of 1,2003 Notary Public Sharon L Fid, Notary PutIc
- MY-m Ex#res January 29,0 Nr7
- Membr, Penrtsv'nla Associaton of Notaie
CAW-03-1608 (1)
I am Manager, Regulatory and Licensing Engineering, in Nuclear Services, Westinghouse Electric Company LLC ("Westinghouse"), and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rule making proceedings, and am authorized to apply for its withholding on behalf of the Westinghouse Electric Company LLC.
(2)
I am making this Affidavit in conformance with the provisions of 10 CFR Section 2.790 of the Commission's regulations and in conjunction with the Westinghouse application for withholding accompanying this Affidavit.
(3)
I have personal knowledge of the criteria and procedures utilized by the Westinghouse Electric Company LLC in designating information as a trade secret, privileged or as confidential commercial or financial information.
(4)
Pursuant to the provisions of paragraph (b)(4) of Section 2.790 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i)
The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse.
(ii)
The information is of a type customarily held in confidence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The application of that system and the substance of that system constitutes Westinghouse policy and provides the rational basis required.
Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:
(a)
The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of 2
CAW-03-1608 Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.
(b)
It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g., by optimization or improved marketability.
(c)
Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.
(d)
It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.
(e)
It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.
(f)
It contains patentable ideas, for which patent protection may be desirable.
There are sound policy reasons behind the Westinghouse system which include the following:
(a)
The use of such information by Westinghouse gives Westinghouse a competitive advantage over its competitors. It is, therefore, withheld from disclosure to protect the Westinghouse competitive position.
(b)
It is information that is marketable in many ways. The extent to which such information is available to competitors diminishes the Westinghouse ability to sell products and services involving the use of the information.
(c)
Use by our competitor would put Westinghouse at a competitive disadvantage by reducing his expenditure of resources at our expense.
3
CAW-03-1608 (d)
Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage. If competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby depriving Westinghouse of a competitive advantage.
(e)
Unrestricted disclosure would jeopardize the position of prominence of Westinghouse in the world market, and thereby give a market advantage to the competition of those countries.
(f)
The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage.
(iii)
The information is being transmitted to the Commission in confidence and, under the provisions of 10 CFR Section 2.790, it is to be received in confidence by the Commission.
(iv)
The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best of our knowledge and belief.
(v)
The proprietary information sought to be withheld in this submittal is that which is appropriately marked in SG-SGDA-02-43-P, "Comanche Peak Steam Electric Station 1RF09 Outage Condition Monitoring Report and Preliminary Cycle 10 Operational Assessment" (Proprietary) and SG-SGDA-03-03-P, "Comanche Peak Steam Electric Station Unit 1 Cycle 10 Operational Assessment" (Proprietary), being transmitted by TXU Energy letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk.
This information is part of that which will enable Westinghouse to:
(a) Provide or endorse documentation in support of methods for the justifying operating cycle lengths based on steam generator tube conditions.
4
5 CAW-03-1608 (b) Provide the applicable engineering evaluation that establishes justification for operating cycle lengths based on steam generator tube conditions.
Further this information has substantial commercial value as follows:
(a)
Westinghouse plans to sell the use of similar information to its customers for purposes of the justification of operating cycle times.
(b)
Westinghouse can sell support and defense of the methodology in the licensing process.
(c)
The information requested to be withheld reveals the distinguishing aspects of a methodology that was developed by Westinghouse.
Public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar evaluations and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
The development of the technology described in part by the information is the result of applying the results of many years of experience in an intensive Westinghouse effort and the expenditure of a considerable sum of money.
In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and a significant manpower effort, having the requisite talent and experience, would have to be expended.
Further the deponent sayeth not.
CAW-03-1608 PROPRIETARY INFORMATION NOTICE Transmitted herewith are proprietary and/or non-proprietary versions of documents furnished to the NRC in connection with requests for generic and/or plant-specific review and approval.
In order to conform to the requirements of 10 CFR 2.790 of the Commission's regulations concerning the protection of proprietary information so submitted to the NRC, the information which is proprietary in the proprietary versions is contained within brackets, and where the proprietary information has been deleted in the non-proprietary versions, only the brackets remain (the information that was contained within the brackets in the proprietary versions having been deleted). The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the affidavit accompanying this transmittal pursuant to 10 CFR 2.790(b)(1).
CAW-03-1608 COPYRIGHT NOTICE The reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted to make the number of copies of the information contained in these reports which are necessary for its internal use in connection with generic and plant-specific reviews and approvals as well as the issuance, denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license, permit, order, or regulation subject to the requirements of 10 CFR 2.790 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding. With respect to the non-proprietary versions of these reports, the NRC is permitted to make the number of copies beyond those necessary for its internal use which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, DC and in local public document rooms as may be required by NRC regulations if the number of copies submitted is insufficient for this purpose. Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.